My 90 4x4 pickup has a bad vibration from the back. when i push in my clutch the vibration goes away and when i let off the gas. when i accelerate it vibrates. im guessing its either the driveshaft or rear end. where the driveshaft joins together it has a little slack and im not sure how much slack i should have in the rear end. any knowledge would help..... my transfer case bearings are good on the yoke, i thought that might be it but the bolt was tight and no slack.

 

No real insight here, but your driveshaft/rear end are still turning at speed regardless of whether you're in gear or neutral. I'd think if it was a driveshaft/u-joint issue, it would still vibrate even if you were going 50mph in neutral.

 

it vibrates when the engine puts pressure on the driveshaft/rear end. my driveshaft had a little play in the splines in the middle of the shaft when u push up or down, could this be it? it still vibrates when i let off the gas just not as bad, and progresses the faster i go......

 

I had this problem for a lomg time, and I tried everything to correct it only to find out it was my u joints. The funny thing was, there was no play in my driveshaft. But when the wheels were off of the groung, it did. Also I was able to move the driveshaft up and down a little in the rear.

Keith

 

I second the U-joints. The almost exact same thing happened to my dad's Explorer. Gas=SHAKEEEEEE, no gas=ah, that's smooth.

Turned out it was one of the u joints.